Principles of Operation

Horn

Principles of Operation

The Body Control Module (BCM) supplies the switched and control voltage to the horn relay (integrated into the BCM (Body Control Module) ).

The horn switch consists of 2 sets of contacts separated by springs. The lower set is connected to ground and the upper set is connected to the horn signal circuit. When the driver air bag module is pressed, it pushes down on the upper set of contacts, collapsing the springs and allowing the contacts to touch. When the contacts touch, it completes the circuit and provides the ground signal which is routed through the clockspring and Steering Column Control Module (SCCM). The horn relay (integral to the BCM (Body Control Module) ) is energized and the horn sounds.

The BCM (Body Control Module) provides a momentary ground to the horn relay when the anti-theft system is armed, and an alternating on/off ground when the panic button is pressed on the Remote Keyless Entry (RKE) transmitter.